Sample test cards

ABSTRACT

The present invention is directed to sample test cards having an increased sample well capacity for analyzing biological or other test samples. In one embodiment, the sample test cards of the present invention comprises a fluid channel network disposed in both the first surface and the second surface and connecting the fluid intake port to the sample wells, the fluid channel network comprising at least one distribution channels, a plurality of fill channels operatively connected to the at least one distribution channel, a plurality of through-channels operatively connected to one or more of the fill channels and a plurality of horizontally orientated fill ports operatively connecting the fill channels to the sample wells. In another embodiment, the sample test cards may comprise a fluid channel network comprising a first distribution channel disposed on a first surface, the first distribution channel comprising a fluid flow path from an fluid intake port to a plurality of second distribution channels or diffusion channels, wherein the second distribution channel or diffusion channels further comprise a plurality of diffusion barriers or “islands” operable to interrupt fluid flow between opposing sample wells, and wherein the second distribution channels or diffusion channels are operatively connected to the sample wells by a plurality of fill channels. The test card of this invention may comprise from 80 to 140 individual sample wells, for example, in a test card sample test cards of the present invention have a generally rectangular shape sample test card having dimensions of from about 90 to about 95 mm in width, from about 55 to about 60 mm in height and from about 4 to about 5 mm in thickness.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 61/416,557, entitled, “Improved Sample Test Cards”,filed Nov. 23, 2010, which is incorporated herein.

FIELD OF THE INVENTION

The invention relates to improved sample test cards, which have anincreased sample well capacity for analyzing biological or othersamples.

BACKGROUND OF THE INVENTION

Sample test cards have been used to analyze blood or other biologicalsamples in a spectroscopic or other automated reading machine. Suchmachines receive a small test card, roughly the size of a playing card,in which biological reagents, nutrients or other material is depositedand sealed, prior to injection of patient samples.

The test card contains the reagents and receives the patient samples ina series of small wells, formed in the card in rows and columns andsealed, typically with tape on both sides. The test cards are filledwith patient sample material through fine hydraulic channels formed inthe card. The microorganisms in the samples may then be permitted togrow or reactions to proceed, generally over a period of up to a fewhours, although the period varies with the type of bacteria or othersubstance analyzed and sample used.

The current assignee has commercialized instruments for fast, accuratemicrobial identification, and antimicrobial susceptibility testing(e.g., Vitek® 2 and Vitek® Compact). These instruments include anincubation stations that maintains sample test cards at a preciselycontrolled temperature to enhance microorganism growth in the individualsample wells. The incubation station includes a rotating carousel thathas a plurality of slots for receiving test sample cards. The carouselis vertically mounted and rotates about a horizontal axis. This rotationabout the horizontal axis during incubation causes the test card to berotated through 360° from a normal “upright” card position, through an“inverted” or “upside-down” card position and then back again to an“upright” position. After the incubation, the samples contained in thewells are placed in front of a laser, fluorescent light or otherillumination source. The content of the sample in a given well can thenbe deduced according to readings on the spectrum, intensity or othercharacteristics of the transmitted or reflected radiation, since theculture of different bacteria or other agents leave distinctivesignatures related to turbidity, density, byproducts, coloration,fluorescence and so forth. The instruments for reading the test cardsand the incubation carousel are further described in U.S. Pat. Nos.5,762,873; 5,888,455; 5,965,090; 6,024,921; 6,086,824; 6,136,270;6,156,565; and 7,601,300, the contents of which are incorporated hereinby reference herein.

Despite the general success of test cards in this area, there is anongoing desire to improve the performance of the cards and readings ontheir samples. It is for example an advantage to impress more reactionwells in a given card, so that a greater variety of reactions andtherefore discrimination of samples can be realized. A given facilitymay have only one such machine, or be pressed for continuous analysis ofsamples of many patients, as at a large hospital. Conducting as manyidentifying reactions on each sample as possible is frequentlydesirable, yielding greater overall throughput.

It has also been the case that as the total number of reaction wells ona given card has increased, while the card size has remained constant,the wells have necessarily been formed increasingly close together. Withthe sample wells crowding each other on the card, it has become morelikely that the sample contained in one well can travel to the nextwell, to contaminate the second well. The threat of increasedcontamination comes into play especially as card well capacity increasesabove 30 wells.

The current Vitek® 2 disposable product family uses a sample test cardcontaining 64 individual sample wells into which chemicals can bedispensed for the identification and susceptibility testing ofmicroorganisms in the diagnosis of infectious disease. Each of fillchannels of the 64 well test card descend to and enter sample wells atan angle, which results in the natural flow of the sample fluid downthrough the fill channels by gravity, and resistance to small pieces ofundissolved material flowing back up into the fluid circuitry. The fluidflow paths thoroughly dispersed over card, including both front and rearsurfaces, also result in a longer total linear travel of the flowingfluid than conventional cards. The increased well-to-well distance leadsto a reduction in the possibility of inter-well contamination. Theaverage well-to-well distance of fluid flow channels on the 64 well cardis to approximately 35 mm, significantly more than the 12 mm or so onmany older card designs. The 64 well test card is further described, forexample, in U.S. Pat. Nos. 5,609,828; 5,746,980; 5,869,005; 5,932,177;5,951,952; and USD 414,272, the contents of which are incorporatedherein by reference herein.

However, as previously discussed, the incubation carousel employed inthe Vitek® 2and Vitek® compact instruments rotates the test cardsthrough a 360° rotation from a normal “upright” card position, throughan “inverted” or “upside-down” card position and then back again to an“upright” position. This rotation of the card can lead to leaking of thesample well contents into the fill channels of prior art cards like the64 well card where the fill channels descend to and enter sample wellsat an angle. In the case of the 64 well card, the potential forwell-to-well contamination is still mitigated by the large distancebetween wells. However, this requirement for longer distances betweenthe wells limits the total number of wells that can fit on a test cardof standard size.

In the case of identification, the use of 64 reactions wells tends to besufficient. However, employing only 64 wells in determining antibioticsusceptibility is limiting. Increasing the number of wells in the cardwould allow improved performance by using more wells for a singleantibiotic test as well as increase the number of antibiotics that couldbe evaluated in a single card. Accordingly, there is a need to increasethe total well capacity in a standard test card while maintaining thereduction in the possibility of inter-well contamination. The novel testcards disclosed herein satisfy this goal without requiring significantchanges to instruments designed to read each well during incubation.

SUMMARY OF THE INVENTION

We disclose herein design concepts for novel sample test cards thatprovide an increase in the total number of sample wells contained withina test card of standard dimensions. These design concepts are capable ofdelaying and/or preventing chemicals front migrating from one well toanother during card filling and incubation.

In one possible design, a sample test card is provided comprising: (a) acard body defining a first surface and a second surface opposite thefirst surface, a fluid intake port and a plurality of sample wellsdisposed between the first and second surfaces, the first and secondsurfaces sealed with a sealant tape covering the plurality of samplewells; (b) a fluid channel network disposed in both the first surfaceand the second surface and connecting the fluid intake port to thesample wells, the fluid channel network comprising at least onedistribution channels, a plurality of fill channels operativelyconnected to the at least one distribution channel, a plurality ofthrough-channels operatively connected to one or more of the fillchannels and a plurality of horizontally orientated fill portsoperatively connecting the fill channels to the sample wells; and (c)wherein the test card comprises from about 80 to about 140 total samplewells. In other embodiments, a sample test card in accordance with thisdesign concept may comprise 80, 88, 96, 104, 108, 112, 120, 126, 135 or140 individual sample wells.

In another embodiment, the preset invention is directed to an improvedsample test card being from about 90 to about 95 mm in width, from about55 to about 60 mm in height and from about 4 to about 5 mm thick, havinga substantially flat card body with a first surface and a second surfaceopposite to said first surface, an intake port formed in said card body,a plurality of sample wells formed in said card body, and a first fluidflow distribution channel, operatively connected to said intake port andtraversing a portion of the first surface to distribute a fluid samplefrom said intake port to a first group of said sample wells and a secondfluid flow distribution channel, operatively connected to said intakeport traversing said second opposite surface to distribute a fluidsample from said intake port to a second group of said wells, said firstand second fluid flow distribution channels thereby supplying fluidsamples to said first and second groups of sample wells, wherein theimprovement comprises said test card having from about 80 to about 140total sample wells. In other embodiments, a sample test card inaccordance with this design concept may comprise 80, 88, 96, 104, 108,112, 120, 126, 135 or 140 individual sample wells.

In another possible design, a sample test card is provided comprising:(a) a card body defining a first surface and a second surface oppositethe first surface, a fluid intake port and a plurality of sample wellsdisposed between the first and second surfaces, the first and secondsurfaces sealed with a sealant tape covering the plurality of samplewells; and (b) a fluid channel network connecting the fluid intake portto the sample wells, the fluid channel network comprising a firstdistribution channel disposed on the first surface, the firstdistribution channel comprising a fluid flow path from the fluid intakeport to a plurality of second distribution channels or diffusionchannels, wherein the second distribution channel or diffusion channelsfurther comprise a plurality of diffusion barriers or “islands” operableto interrupt fluid flow between opposing sample wells, and wherein thesecond distribution channels or diffusion channels are operativelyconnected to the sample wells by a plurality of fill channels. In someembodiments, the test cards of this design concept may comprise from 80to 140 individual sample wells, or from about 96 to about 126 individualsample wells, each of which receives a test sample, for example abiological sample extracted from blood, other fluids, tissue or othermaterial of a patient, for spectroscopic or other automated analysis. Inother embodiments, the sample test card in accordance with this designconcept may comprise 80, 88, 96, 104, 108, 112, 120, 126, 135 or 140individual sample wells.

BRIEF DESCRIPTION OF THE FIGURES

The various inventive aspects will become more apparent upon readingfollowing detailed description of the various embodiments along with theappended drawings, in which:

FIG. 1—is a front view of the front surface of a sample test card, inaccordance with one design concept of the present invention. As shown,the sample test card comprises 112 sample wells, an intake reservoir, aplurality of distribution channels and a plurality of well ports.

FIG. 2—is a front view of the rear surface of the sample test card shownin FIG. 1.

FIG. 3—is a top view showing the top edge of the sample test card ofFIG. 1.

FIG. 4—is a bottom view showing the bottom edge of the sample test cardof FIG. 1.

FIG. 5—is a side view showing the first or leading side edge of thesample test card of FIG. 1.

FIG. 6—is a side view showing the second g side edge and intake port ofthe sample test card of FIG. 1.

FIG. 7—is a front view of the front surface of a sample test card, inaccordance with another design concept of the present invention. Asshown, the sample test card comprises 112 sample wells, an intakereservoir, a plurality of distribution channels and a plurality of wellports.

FIG. 8—is a front view of the rear surface of a sample test card, inaccordance with the design concept of FIG. 7. As shown, the sample testcard comprises 112 sample wells and an intake reservoir.

DETAILED DESCRIPTION OF THE INVENTION

The improved sample test cards of the present invention have a generallyrectangular shape and are in standard dimensions of from about 90 toabout 95 mm in width, from about 55 to about 60 mm in height and fromabout 4 to about 5 mm in thickness. In one embodiment, the sample testcards of the present invention are about 90 mm wide, about 56 mm highand about 4 mm thick. The test cards of this invention may comprise from80 to 140 individual sample wells, or from about 96 to about 126individual sample wells, each of which receives a test sample, forexample a biological sample extracted from blood, other fluids, tissueor other material of a patient, for spectroscopic or other automatedanalysis. In other embodiments, the sample test cards may comprise 80,88, 96, 104, 108, 112, 120, 126, 135 or 140 individual sample wells. Thesample wells are typically arranged in a series of horizontal rows andvertical columns and may comprise from about 8 to about 10 rows of fromabout 10 to about 16 columns of wells. The biological sample may be adirect sample from the patient, or be a patient sample which isextracted, diluted, suspended, or otherwise treated, in solution orotherwise. Furthermore, in accordance with the present invention, thesample test card comprises a fluid channel network or a plurality offluid flow channels (e.g., distribution channels and fill channels) fortransport of a fluid test sample from an intake port to each of theindividual sample wells. The distribution channels and fill channels(e.g., as schematically illustrated in FIGS. 1-2), may be preferablyformed in full-radius style, that is, as a semicircular conduit, ratherthan a squared-off channel as in some older designs. The full-radiusfeature has been found by the inventors to reduce friction and fluidturbulence, further enhancing the performance of test card 2. The sampletest cards are generally used in a landscape orientation.

The test cards may be made of polystyrene, PET, or any other suitableplastic or other material. The test cards may be tempered duringmanufacture with a softening material, so that crystalline rigidity, andresultant tendency to crack or chip, is reduced. Test cards for instancemay be manufactured out of a blend of polystyrene, approximately 90% ormore, along with an additive of butyl rubber to render the card slightlymore flexible and resistant to damage. In some embodiments, the testcards may also be doped with coloring agents, for instance titaniumoxide to produce a white color, when desired.

The test cards of the invention may be of use in identifying and/orenumerating any number of microorganisms, such as bacterial and/or otherbiological agents. Many bacteria lend themselves to automatedspectroscopic, fluorescent and similar analysis after incubation, as isknown in the art. The transmission and absorption of light is affectedby the turbidity, density and colormetric properties of the sample.Fluorescent reactions may be performed as well, independently or alongwith spectroscopic or other measurements. If fluorescent data aregathered, use of a coloring agent in test cards may be preferred, sincean opaque card reduces or eliminates the scattering of fluorescentemissions throughout the card, as can occur with a translucent material.Other types of detection and analysis can be done on the test cards,including testing of susceptibility of microorganisms to antibiotics ofdifferent types, and at different concentrations, so that the test cardsare general-purpose instrument.

One design concept of the invention is illustrated in FIGS. 1-6. Thisdesign provides an improved sample test card 2, having a generallyrectangular shape and in standard dimensions. The test card 2 furthercomprises a plurality of sample wells 4 and has a first or front surface6 and a second or rear surface 8, opposite said front surface 6, a firstor leading side edge 10, a second or trailing side edge 12, a top edge14, and a bottom edge 16. The illustrated test card 2 of this embodimentcontains a total of 112 individual sample wells 4, which extendcompletely through the test card from the front surface 6 to the rearsurface 8, and each of which are capable of receiving a test sample foranalysis,as previously described. As shown in FIGS. 1-2, the samplewells can be arranged in 8 rows of 14 columns of wells, therebyproviding a total of 112 individual sample wells. However, as would bereadily apparent to one of skill in the art, other well arrangements arepossible.

To receive sample fluid, the test card 2 includes a sample intake plenumor port 18 (see FIG. 6), typically located on a perimeter edge (e.g.,the second or trailing edge 16) in an upper right corner of the testcard 2. The sample wells 4 of test card 2 contain dry biologicalreagents which are previously put in place in the sample wells 4, byevaporative, freeze-drying or other means. Each well 4 can hold adeposit of a different reagent that can be used for identifyingdifferent biological agents and/or for determining the antimicrobialsusceptibility of different biological agents, as desired. The injectedpatient sample dissolve or re-suspend the dry biological reagents ineach well 4 for analysis.

As is well known in the art, intake port 18 receives a fluid injectiontip and related assembly (schematically illustrated as 20), throughwhich the sample fluid or other solution which arrives to dissolve thebiological reagents in each well 4 is injected, under a vacuum pulled ontest card 2 (typically 0.7-0.9 PSIA), then released to atmosphericpressure. Injection port 18 includes a small intake reservoir 22 formedas a roughly rectangular hole through the test card 2, which receivesincoming fluid, and acts as a fluid buffer. When the sample is injectedinto the card, a short segment of the sample tip can be pinched off orheat-sealed and left in place in intake port 18, acting as a sealingplug. After the test fluid (patient sample or other solution) enters theintake port 18 the fluid flows through a fluid flow path comprising aseries of fluid flow channels (e.g., distribution channels and fillchannels) for transport of a fluid test sample from the intake port 18to each of the individual sample wells 4, as described in more detailherein.

It has been unexpectedly discovered that by employing the use ofhorizontally orientated well till ports the average fluid flow pathdistance between wells can be reduced, thereby allowing for an increasedwell capacity, while maintaining strict inter-well contaminationstandards. Furthermore, it has also been discovered that by reducing thewell sizes by approximately a third enough surface area is recovered toallow for an increased well capacity in a test card having standarddimensions.

As shown in the illustrated design concept (see FIGS. 1-2), the testcard employs a fluid flow path comprising a plurality of distributionchannels, fill channels, through-channels and well fill ports, whichconnects to, and fill, each of the individual sample wells with a testsample. Also, as shown, each of the well fill port connects to andenters the individual sample well in a generally horizontal or widthwisemanner. Applicants have found that the use a horizontally orientatedwell fill port reduces the possibility of well leakage during rotationof the card in the carousel incubator of the Vitek® 2 or Vitek® compactinstruments. Furthermore, in one design possibility, the well fill portsmay have a width of about 0.5 to about 0.6 mm and a depth of about 0.5to about 0.6 mm (i.e., a cross section of from about 0.25 to about 0.36mm²). In contrast, as disclosed elsewhere herein, the fill channels mayhave a width of about 0.2 to about 0.4 mm and a depth of about 0.3 toabout 0.5 mm (i.e., a cross section of about 0.06 to 0.2 mm²). While notwishing to be bound by theory, it is believed that this reduction incross section from the well fill ports to the fill channels may act tofurther slow the migration of any fluid or chemicals that may have leakout of the individual sample wells and into the well fill ports.

As mentioned hereinabove, previous card designs employed the use ofrelatively long fluid flow paths between wells to increase thewell-to-well distance between individual sample wells. The fluid flowpaths thoroughly dispersed over the card, including both front and rearsurfaces, resulted in an average well-to-well distance of approximately35 mm. By contrast, in this design concept, the average flow channeldistance between wells is less than 30 mm, or less than 25 mm. Inanother embodiment, the average well-to-well distance between individualsample wells 4 is from about 20 to about 25 mm. Again, Applicants havefound that by employing the use of horizontally orientated well fillports the average fluid flow path distance between wells can be reduced,thereby allowing for an increased well capacity, while maintainingstrict inter-well contamination standards.

Accordingly, the combination of reduced well sizes, horizontallyorientated well fill channels and shorter average well-to-well fluidflow path, has allowed for an increased well capacity within a test cardhaving standard dimensions. The contamination rate is also reduced bythe fact that the volume of the channels along the fluid circuit variesslightly along the overall circuit traveled by a given sample. That is,the through-channels, the main distribution channels and other segmentsof the paths have cross-sectional areas which, although all relativelyfine, may differ slightly. The change in volume over the path tends toretard the progression of contamination, as do dog-legged or kinkedsections of connecting conduits. The test cards of this design conceptmay comprise from 80 to 140 individual sample wells, or from about 96 toabout 126 individual sample wells. In one embodiment, the sample testcards may comprise 80, 88, 96, 104, 108, 112, 120, 126, 135 or 140sample wells.

Referring now to FIGS. 1-6, the illustrated test card 2 of this designconcept will be described in further detail. As the test fluid (i.e.,patient sample or other solution) enters intake port 18 it collects inintake reservoir 22 and travels along a first distribution channel 30that leads away from the intake reservoir 22. First distribution channel30 comprises a relatively long channel, which extends in a substantiallyhorizontal or widthwise manner across the front surface 6 of the testcard 2 and parallel to the top edge 14 of the card. In one embodimentthe first distribution channel 30 may comprises a fluid flow channelhaving a width of about 0.5 mm and a depth of about 0.5 mm (i.e., across section of approximately 0.25 mm²).

First distribution channel 30 is tapped at intervals along its length bya series or plurality of first fill channels 40, which generally descendfrom first distribution channel 30 toward the sample wells 4 in each ofthe fourteen illustrated columns. As shown in FIG. 1, first fillchannels 40 are relatively short channels (which may be kinked) thatextend down from first distribution channel 30 into respective wellports 24, which function to connect, and thereby fill the individualsample wells 4 located in the first and third rows (down from the topedge 14) of test card 2. In one embodiment, first fill channels 40 maycomprise a fluid flow channel having a width of about 0.2 to about 0.4mm and a depth of about 0.3 to about 0.5 mm (i.e., a cross section ofabout 0.06 to 0.2 mm²). In another embodiment, the first fill channels40 have a width of about 0.3 mm and a depth of about 0.4 mm (i.e., across section of about 0.12 mm²).

Accordingly, the illustrated test card 2 (see FIGS. 1-2) thereforeincludes two rows (the first and third rows down from the top edge ofthe card) by thirteen columns of sample wells built up by connectingchannels through the first distribution channel 30 and series of firstfill channels 40. This provides a set of twenty-six (26) total samplewells that are filled via the first distribution channel 30.

Like the first distribution channel 30, the second distribution channel32 is located on the front surface 6 of the test card 2 leading from theintake reservoir 22. The second distribution channel 32 descendvertically down (and which may be kinked, as shown) from the intakereservoir 22. The second distribution channel 32 leads to a second fillchannel 42 and/or well ports 24, thereby connecting, and fillingadditional sample wells 4.

As shown the illustrated test card 2 includes two rows (again, first andthird rows down from the top edge 14 of the card) by a single, orfourteenth column, of sample wells built up by connecting the seconddistribution channel 32 and/or second fill channel 42. Thus, two (2)sample wells that are filled via the second distribution channel 32.

In addition to the introduction of fluid through the path of firstdistribution channel 30 and first fill channels 40, fluid also travelsto wells below the first and third row of wells through other fluid flowchannels. More specifically, intake reservoir 22 also connects to athird distribution channel 34 formed on the opposite or rear surface 8of the test card 2, which also leads away from the intake reservoir 22.The third distribution channel 34 extends substantially along the widthof test card 2, generally parallel to the top edge 14 of the test card2. In one embodiment, the third distribution channel 34 may comprise afluid flow channels having a width of about 0.5 mm and a depth of about0.5 mm (i.e., a cross section of approximately 0.25 mm²).

Like the first distribution channel 30, the third distribution channel34 is tapped above the fourteen illustrated columns of sample wells 4 bya series of third fill channels 44, each of which leads to series ofthrough-channels 26. The through-channels 26 are small apertures,approximately 1 mm in diameter, formed cleanly through the body of testcard 2, forming conduits or vias from one surface of the card to theother. The through-channels 26 are connected to additional well fillchannels 44 on the front surface 6 of the card forming a short link tothe respective well ports 24 and samples wells 4. Accordingly, the thirdfill channels 44 deliver the fluid to the sample wells from the oppositeor rear side 8 of the test card 2, creating a different fluid flowcircuit which extends from intake reservoir 22. That is, this pathinvolves the third distribution channel 34 and third fill channels 44 onthe rear surface of the card, through the body of the card by way ofthrough-channels 26, then out to connecting short fill channels 44 andwell ports 24 which deliver the sample to the well 4. In one embodiment,third fill channels 44 may comprise a fluid flow channel having a widthof about 0.2 to about 0.4 mm and a depth of about 0.3 to about 0.5 mm across section of about 0.06 to 0.2 mm²). In another embodiment, thethird fill channels 44 have a width of about 0.3 mm and a depth of about0.4 mm (i.e., a cross section of about 0.12 mm²).

In the illustrated test card of FIGS. 1-2, the third distributionchannel 34 leads to thirteen third fill channels 44, each of which leadsto four through-channels 26 and subsequently to four individual samplewells 4. Accordingly, the illustrated test card 2 therefore includesfour rows (the second, fourth, fifth and seventh rows down from the topedge of the card) by thirteen columns of sample wells built up byconnecting channels through the third distribution channel 34 and seriesof third fill channels 44. This provides a set of 52 total sample wellsthat are filled via the third distribution channel. Likewise, in theillustrated test card (see FIGS. 1-2) each of the thirteen third fillchannels 44 leads to four through-channels 26, giving a total of 52fill-channels 44.

A fourth distribution channel 36 also leads away from the intakereservoir 22 on the rear surface 8 of the test card 2. The fourthdistribution channel 36 descends substantially vertically along the rearsurface 8 of the card 2 parallel to the first 10 and second 12 sideedges of the card 2. Like the other distribution channels describedabove, in one embodiment, the fourth distribution channel 36 maycomprise a fluid flow channels having a width of about 0.5 mm and adepth of about 0.5 mm (i.e., a cross section of approximately 0.25 mm²).

The fourth distribution channel 36 first leads to a series or pluralityof fourth fill channels 46, which comprise short channels located on therear surface 8 of the test card 2, each of which leads to athrough-channel 26 forming a conduit or via from one surface of the cardto the other, and which are subsequently connected to additional shortfill channels 46 on the front surface 6 of the card 2. The fill channels46 on the front surface 6 of the card 2 form a short link to therespective well ports 24 and samples wells 4. Like the third fillchannels 44, the fourth fill channels 46 deliver the fluid to the samplewells 4 from the opposite or rear side 8 of the test card 2, creating adifferent fluid flow circuit, which extends from intake reservoir 22.

As shown the illustrated test card 2, the fourth distribution channel 36leads to four through-channels 26 each of which subsequently lead to anindividual sample well 4 in second, forth, fifth and seventh rows (i.e.,the second, fourth, fifth and sixth rows down from the top edge of thecard) of the fourteenth column on the front surface 6 of the test card2. Accordingly, four (4) sample wells that are filled via the fourthdistribution channel 36 and associated through-channels 26.

The fourth distribution channel 36 also leads to a distributionthrough-channel 28 located in the bottom corner of the test card 2, andwhich leads through the card to a fifth distribution channel 38 locatedin the front surface 6 of the test card 2. More specifically, the fourthdistribution channel 36 is in fluid connection with intake reservoir 22,but traces a generally vertical path downward from the reservoir to adistribution through-channel 28, located at a lower right section of thetest card 2. Fluid flows down through the fourth distribution channel36, into the distribution through-channel 28, through the card from therear surface 8 to the front surface 6, and then into the fifthdistribution channel 38. The fifth distribution channel 38, located onthe front surface 6 of test card 2, extends along the lower base of thecard 2 in a generally horizontal or widthwise manner parallel to thebottom edge 16 of the card. In one embodiment, the fifth distributionchannel 38 may comprise a fluid flow channels having a width of about0.5 mm and a depth of about 0.5 mm (i.e., a cross section ofapproximately 0.25 mm²).

Rising up from the fifth distribution channel 38 are a series orplurality of fifth fill channels 48, which generally resemble the firstfill channels 40 but which extend upward from fifth distribution channel38, rather than downward. However, fifth fill channels 48 perform thesame basic function, delivering the fluid to a series of well ports 24and subsequently to individual sample wells 4.

The illustrated test card 2 (see FIGS. 1-2) therefore includes two rows(the sixth and eighth rows down from the top edge of the card) bythirteen columns of sample wells built up by connecting channels throughthe fourth 36 and fifth 38 distribution channel and series of fifth fillchannels 48. This provides a set of twenty-six (26) total sample wellsthat are filled via the first distribution channel 30.

Accordingly, as mentioned elsewhere herein, the illustrated test card 2of FIGS. 1-6, therefore includes eight rows by fourteen columns ofsample wells (i.e., 112 total individual sample wells) built up by aplurality of distribution channels, fill channels and through-channelsdistributed over the front 6 and rear 8 surfaces of the test card 2.

Also, as shown in FIGS. 1-2, each of the individual sample wells 4includes an associated bubble trap 50, connected to sample well 4 at anupper corner of the well, and located at a height slightly above thewell 4 on the front card surface 6. As known in the art, each bubbletrap 50 is connected to its respective well 4 by a short trap connectingconduit 52, formed as a hollow passage part-way into the card surfaceand forming a short conducting path for trapped gaseous bubbles whichhave been formed in, or communicated to, the well 4 during the injectionoperation, by bacterial or other biological reaction, or otherwise.Bubble trap 50 does not cut through the card completely, insteadconsisting of a depression or well of roughly oval shape, optionallywith a rounded bottom contour, and a volume of from about 2 to about 4cubic mm in the illustrated embodiment. Because the bubble trap 50 islocated at an elevated position above each respective well 4, anygaseous bubbles will tend to rise and be trapped in the depression oftrap 50. With gaseous remnants led off to the bubble trap 50, analyticalreadings on the biological sample can be made more reliably, sincescattering and other corruption of the microbial radiation reading bygas is reduced or eliminated.

The sample wells 4 which receive the fluid from the second distributionthrough-channel circuit, like the sample wells which receive the fluidthrough the (front-planar) first distribution channel, also have bubbletraps 50 associated with them, in the same general above-wellconfiguration.

For mechanical interaction with the automated reading machine, test card2 may also be provided with a series of sensor stop holes 60, locatedalong the uppermost edge of the card. Sensor stop holes 60, illustratedas regularly spaced, rectangular through-holes, permit associatedphotodetectors to detect when a test card 2 mounted in a reading machinehas come into proper alignment for optical reading. In prior art cards,the sensor stop holes were arranged in vertical register with thevertical columns of wells, so that the optical detection of the stophole corresponds exactly to positioning of the sample wells beforeoptical reading devices. However, it has now been discovered that thisprecise alignment of the sensor stop holes with the leading edge of thesample wells can lead to the front edge of the well not being read as aresult of a slight delay in the stopping of the card once the sensorstop holes are detected, and thus, a slight misalignment for opticalreading. Accordingly, in the present embodiment, the sensor stop holes60 are arranged in a vertical alignment slightly ahead of the verticalcolumn of wells 4, so that one optical detection of the stop holes 60occurs and optical reading of the test card 2 initiated, the readingwill start at the front edge of the sample well 3. In accordance withthis embodiment, the sensor stop holes 60 may be aligned from about 0.25to about 2 mm ahead (i.e., closer to the first or leading edge of thetest card 2) of the vertical wells 4. Moreover, aligning the sensor stopholes slightly ahead of the leading edge of the sample well enables theuse of smaller sample wells since the full width of the well can be readby the optical reading machine.

Another advantage of test card 2 of the illustrated design is thatpatient sample and other markings are not introduced directly on thecard itself, in pre-formed segments, as for example shown for example inU.S. Pat. No. 4,116,775 and others. Those on-card striplings andmarkings can contribute to debris, mishandling and other problems. Inthe invention, instead, the card 2 may be provided with bar-coding orother data markings (not shown) by adhesive media, but markings orpre-formed information segments are not necessary (though some could beimprinted if desired) and debris, mishandling, loss of surface area andother problems can be avoided.

Test card 2 furthermore includes, at the lower left corner of the cardas illustrated in FIG. 1, a tapered bezel edge 70. Tapered bezel edge 70provides an inclined surface for easier insertion of test card 2 into,carrousels or cassettes, into slots or bins for card reading, and otherloading points in the processing of the card. Tapered bezel edge 70provides a gently inclined surface, which relieves the need for tighttolerances during loading operations.

Test card 2 also includes a lower rail 80 and an upper rail 82, whichare slight structural “bulges” at along the top and bottom areas of thecard to reinforce the strength and enhance handling and loading of thetest card 2. The extra width of lower and upper rails 80 and 82 alsoexceeds the thickness of sealing material, such as adhesive tape, thatis affixed to the front 6 and rear 8 surfaces of test card 2 for sealingduring manufacture and impregnation with reagents. The raised railstherefore protect that tape, especially edges from peeling, during themaking of the test card 2, as well as during handling of the card,including during reading operations.

As is well known in the art, upper rail 82 may have serrations (notshown) formed along its top edge, to provide greater friction when testcard 2 is transported in card reading machines or otherwise using beltdrive mechanisms. Also, as well known in the art, lower card rail 80 mayalso have formed in it reduction cavities (not shown), which are smallelongated depressions which reduce the material, weight and expense ofthe card by carving out space where extra material is not necessary inthe reinforcing rail 80.

In terms of sealing of test card 2 to contain reagents and othermaterial, it has been noted that sealing tapes are typically used toseal flush against test card 2 from either side, with rail protection.Test card 2 may also includes a leading lip 84 on lower card rail 80,and on upper card rail 82. Conversely, at the opposite end of the testcard 2 there may also be a trailing truncation 86 in both rails. Thisstructure permits sealing tape to be applied in the card preparationprocess in a continuous manner, with card after card having tapeapplied, then the tape cut between successive cards without the tapefrom successive cards getting stuck together. The leading lip 84 andtrailing truncation 86 provides a clearance to separate cards and theirapplied tape, which may be cut at the trailing truncation 86 and wrappedback around the card edge, for increased security against interferencebetween abutting cards. Thus, the trailing truncation or slanted rampfeature 86 ends slightly inward from the extreme edge of the ends of thecard, as shown in FIGS. 1 and 2 to define a portion of the card surfaceor “shelf portion” between the ends of the ramps 86 and the second ortrailing edge 12 of the test card 2, extending across the width of thetest card 2. This shelf portion provides a cutting surface for a bladecutting the tape applied to the card. Further, the ramp 86 facilitatesthe stacking of multiple test sample cards without scuffing of thesealant tape applied to said cards, by allowing the ramps to slide overeach other during a stacking motion with the raised rails preventingscuffing of the tape.

In another design concept of the invention is illustrated in FIGS. 7-8.Like the test card shown in FIGS. 1-6, the design concept illustrated inFIGS. 7-8 provides an roved sample test card 102, having a generallyrectangular shape and in standard dimensions. The test card 102 furthercomprises a plurality of sample wells 104 and has a first or frontsurface 106 and a second or rear surface 108, opposite said frontsurface 106, a first or leading side edge 110, a second or trailing sideedge 112, a top edge 114, and a bottom edge 116. The illustrated testcard 102 of this embodiment contains a total of 112 individual samplewells 104, which extend completely through the test card from the frontsurface 106 to the rear surface 108, and each of which are capable ofreceiving a test sample for analysis, as previously described. However,test cards of this design may comprise from 80 to 128 individual samplewells, or from about 96 to about 140 individual sample wells. In oneembodiment, the sample test cards may comprise 80, 88, 96, 104, 108,112, 120, 126, 135 or 140 sample wells. The sample wells are typicallyarranged in a series of horizontal rows and vertical columns and maycomprise from about 8 to about 10 rows of from about 10 to about 16columns of wells. As shown in FIGS. 7-8, the sample wells 104 can bearranged as fourteen columns of eight wells 104 (i.e., 112 total samplewells).

As with the illustrated test card design shown in FIGS. 1-6, this designconcept will also receive a sample fluid through an intake plenum orport (not shown), typically located on a perimeter edge. As is wellknown in the art, intake port receives a fluid injection tip and relatedassembly (not shown), through which the sample fluid or other solutionwhich arrives to dissolve the biological reagents in each well 104 isinjected, under a vacuum pulled on test card 102 (typically 0.7-0.9PSIA), then released to atmospheric pressure. Also like the first designconcept (see FIGS. 1-6), the injection port of this design will includea small intake reservoir 120 formed as a roughly rectangular holethrough the test card 102, which receives incoming fluid, and acts as afluid buffer. When the sample is injected into the card, a short segmentof the sample tip can be pinched off or heat-sealed and left in place inintake port, acting as a sealing plug. After the test fluid (patientsample or other solution) enters the intake port the fluid will flowthrough a fluid flow path comprising a series of fluid flow channels(e.g., distribution channels and fill channels) for transport of a fluidtest sample from the intake port to each of the individual sample wells,as described in more detail hereinbelow.

As shown in FIGS. 7-8, the illustrated test card 102 employs a fluidflow path comprising a first distribution channel 130, a seconddistribution channel 132, a through-hole 134, a third distributionchannel 136, a plurality of diffusion channels 142, and a plurality offill channels 150, 152, 154 and 156, which connect to, and fill, each ofthe individual sample wells with a test sample. Also, as shown in FIG.7, the plurality of diffusion channels 142 further comprises a series orplurality of diffusion barriers or “islands” 144, which are locatedwithin the diffusion channel between opposing fill channels 150 andoperate to interrupt or impede fluid flow between opposing sample wells104. Also, as shown in FIG. 7, the diffusion channels 144 furthercomprise diffusion zones 146, which comprise a large cross sectionalarea of the diffusion channel between the diffusion barriers or“islands” 144.

As previously described hereinabove, after a test card is filled with atest sample, the dense media contained in each of the wells may flow, orleak, out of the wells and into the fluid flow channels duringincubation of the test card. Once in the fill channels any media thathas leaked out may subsequently flow to adjacent sample wells, therebycontaminating those sample wells.

Applicants have discovered that by employing flow channels (i.e.,diffusion channels 142) having a large cross sectional area and/ordiffusion zones 146, which contain a large volume of the test sample,allows for any media that has leaked out of a sample well to be diluted,thereby reducing the potential for well-to-well contamination.Furthermore, Applicants have discovered that by including features, suchas diffusion barriers or “islands” 144, in the flow channels (i.e.,diffusion channel 142), which operate to disrupt or impede the flow pathbetween wells, the potential effects of well-to-well contamination canbe further mitigated because the diffusion barriers 144 act to re-routeany media that may have leaked out of the sample wells to the diffusionzones 146. More specifically, the use of diffusion barriers 144 whichdisrupt of impede the fluid flow path between wells, forces any mediathat may have leaked out of the sample wells to travel through thediffusion zones 146, which are larger cross-section areas of the flowchannels which contain a relatively larger amount of the test sampleloaded into the test card, thereby allowing for dilution of any leakedmedia. By introducing features to dilute any that has leaked out of awell, the long fluid flow paths between wells required in previous carddesigns can be decreased. The use of a shorter fluid flow path betweenwells allows for an increased well capacity within a test card, whilemaintaining strict inter-well contamination standards. Furthermore, byreducing the well sizes by approximately a third enough surface area isrecovered to allow for an increased well capacity in a test card havingstandard dimensions.

Referring now to FIGS. 7-8, the illustrated test card 102 of this designconcept will be described in further detail. As shown in FIGS. 7-8 thetest card 102 may comprise 112 individual sample wells arranged infourteen columns of eight sample wells 104. As the test fluid (i.e.,patient sample or other solution) enters intake port it collects inintake reservoir 120 and travels along a first distribution channel 130that leads away from the intake reservoir 122. First distributionchannel 130 comprises a relatively long channel, which extends in asubstantially horizontal or widthwise manner across the front surface106 of the test card 102, and parallel to the top edge 114 of the card.In one embodiment the first distribution channel 130 may comprises afluid flow channel having a width of about 0.5 mm and a depth of about0.5 mm (i.e., a cross section of approximately 0.25 mm²).

First distribution channel 130 is tapped at intervals along its lengthby a series or plurality of diffusion channels 142, which generallydescend from the first distribution channel 130 between columns ofsample wells 104. As shown, for example in FIG. 7, the diffusion channel142 may comprise a narrow entrance channel 140 that directly taps thefirst distribution channel 130 and the main channel or diffusion channelbody 142. Also, as shown, the test card 102 may comprise 14 columns of 8sample wells (i.e., 112 total wells).

In the embodiment shown in the figures, test card 102 comprises a set ofseven total diffusion channels 142, each connected to a plurality ofsample well 104 via a plurality of first fill channels 150. Also asshown, each of the diffusion channels 142 further provides a diffusionbarrier 144, which disrupts the flow and a diffusion zone 146, whichoperates to dilute any media that has leaked out of a sample well 104.In one embodiment, the diffusion channel 142 comprises a fluid flowchannel having a width of about 2 mm, and a depth of about 0.6 mm.Furthermore, as discussed above, the diffusion channel 132 may comprisetherein a plurality of diffusion barriers 144 which act to which operateto disrupt or impede the flow path between wells. In general, thediffusion barriers 144 are placed within the diffusion channel 142between opposing sets of sample wells 104, and can be spaced apart byabout 2 mm within the second distribution channel 132, thereby creatingthe diffusion zones 146. The diffusion barriers 144 themselves can beabout 1.2 mm in width and about 2 mm in height. The diffusion zones 146provides for a dilution reservoir within the diffusion channel 142located between opposing sample wells 104. The diffusion zones 146generally have a width of about 2 mm, a height of about 2 mm and depthof about 0.6 mm (i.e., a volume of about 2.4 mm³).

As shown in FIGS. 7-8, the sample test card 102 further comprises asecond distribution channel 132 located on the rear surface 108 of thetest card 102. In the exemplified design of FIGS. 7-8, the seconddistribution channel 132 comprises a relatively long channel, whichextends in a substantially vertical manner down the rear surface 108 ofthe test card 102, and parallel to the second or trailing side edge 112of the card 102. The second distribution channel 132 leads to a throughchannel 134 located in the bottom corner of the test card 102, throughthe card, and subsequently to a third distribution channel 136 locatedon the front surface 106 of the card. Third distribution channel 136comprises a relatively long channel, which extends in a substantiallyhorizontal or widthwise manner across the front surface 106 of the testcard 102, and parallel to the bottom edge 116 of the card. In oneembodiment the second distribution channel 132 and third distributionchannel 136 may comprises a fluid flow channel having a width of about0.5 mm and a depth of about 0.5 mm (i.e., a cross section ofapproximately 0.25 mm²).

As shown in FIGS. 7-8, the sample test card 102 comprises a plurality offill channels 150, 152, 154 and 156, which are operably connected to,and fill individual sample wells 104. The fill channels 150, 152, 154and 156 are relatively short channels (which may be kinked) that extendhorizontally and/or vertically from the distribution channels 130 and/ordiffusion channels 142, which function to connect, and thereby fill theindividual sample wells 104 of test card 102. In general, providingkinked fill channels, which extend vertically and horizontally acrossthe surface of the test card, allows for increased channel length,thereby reducing and/or eliminating the possibility of well-to-wellcontamination. In the exemplified embodiment of FIGS. 7-8, a pluralityof first fill channels 150 connect the diffusion channels 146 with, andthereby fill, a set of first sample wells 104. A plurality of secondfill channels 152 lead from, or tap, the first distribution channel 130,connecting the first distribution channel 130 with, and thereby filling,a second set of individual sample wells 104. Also as shown, a pluralityof third fill channels 154 lead from, or tap, the third distributionchannel 136, connecting the third distribution channel 136 with, andthereby filling, a third set of individual sample wells 104.Furthermore, as shown, a fourth fill channel 156 may be provided thatconnects the intake reservoir 120 with, and thereby fills, an individualsample well 104. In one embodiment, the plurality of fill channels 150,152, 154 and 156 may comprise fluid flow channels having a width ofabout 0.2 to about 0.4 mm and a depth of about 0.3 to about 0.5 mm(i.e., a cross section of about 0.06 to 0.2 mm²). In another embodiment,the fill channels 134 have a width of about 0.3 mm and a depth of about0.4 mm (i.e., a cross section of about 0.12 mm²).

Accordingly, the illustrated test card 102 (see FIGS. 7-8) includesfourteen columns each having eight sample wells, built up by connectingchannels through a fluid flow path comprising the first, second andthird distribution channels 130, 132 and 136, diffusion channels 142 andfill channels 150, 152, 154 and 156. This provides a set of one hundredand twelve (112) total sample wells that are filled by the fluid flowpath of this design concept.

As described above in relation to the first design concept (see FIGS.1-6), the design concept illustrated in FIGS. 7-8 may further comprise aplurality of bubble traps 158, associated with, or connected to, each ofthe individual sample wells 104. The test cards 102 of this designconcept may also comprise a series of sensor stop holes 160, a barcodeor other data marking (not shown), a tapered bezel edge 170, and/orlower and upper rails 180, 182, optionally with associated leading lip184 or trailing truncation 186, as described in more detail hereinabove.

The foregoing description of the improved test cards of the invention isillustrative, and variations on certain aspects of the inventive systemwill occur to persons skilled in the art. The scope of the invention isaccordingly intended to be limited only by the following claims.

1-26. (canceled)
 27. A sample test card, comprising: a card body havinga width between about 90 mm and about 95 mm, a length between about 44mm and about 60 mm, and a thickness between about 4 mm and about 5 mm,the card body defining: a first surface and a second surface oppositethe first surface; a fluid intake port; a plurality of sample wellscomprising a first group of sample wells and a second group of samplewells, wherein the plurality of sample wells comprise more than 64sample wells; a first fluid flow distribution channel defined at thefirst surface of the card body, wherein the first fluid flowdistribution channel is fluidically connected to the fluid intake portand the first group of sample wells; and a second fluid flowdistribution channel defined at the second surface of the card body,wherein the second fluid flow distribution channel is fluidicallyconnected to the fluid intake port and the second group of sample wells.28. The test card of claim 27, wherein the plurality of sample wellscomprise from 80 to 140 sample wells.
 29. The test card of claim 27,wherein the plurality of sample wells comprise 104 sample wells.
 30. Thetest card of claim 29, wherein the 104 sample wells are arranged asthirteen columns of eight sample wells.
 31. The test card of claim 27,wherein the first and second surfaces are sealed with a sealant tapecovering the plurality of sample wells.
 32. The test card of claim 27,wherein the plurality of sample wells are disposed between the firstsurface and the second surface.
 33. The test card of claim 27, furthercomprising a plurality of fill channels connected to at least one of thefirst fluid flow distribution channel and the second fluid flowdistribution channel, and a plurality of horizontally oriented fillports connecting the plurality of fill channels to a respective one ofthe first group of sample wells and the second group of sample wells,wherein each of the fill ports extends in a widthwise direction of thecard body, wherein each of the fill ports extends perpendicular to aportion of the fill channels, wherein the fill channels have a reducedcross-section compared to the fill ports.
 34. The test card of claim 33,wherein the plurality of horizontally fill ports are perpendicular tothe at least one of the first fluid flow distribution channel and thesecond fluid flow distribution channel.
 35. The test card of claim 33,wherein the plurality of fill channels are perpendicular to the at leastone of the first fluid flow distribution channel and the second fluidflow distribution channel at a junction between the fill channels andthe at least one of the first fluid flow distribution channel and thesecond fluid flow distribution channel.
 36. The test card of claim 33,wherein a width direction of the test card is defined parallel to alongest edge of the card body, and wherein each of the fill ports isoriented parallel to the longest edge of the card body.
 37. The testcard of claim 33, wherein the horizontally orientated fill portscomprise a width of about 0.5 to about 0.6 mm and a depth of about 0.5to about 0.6 mm.
 38. The test card of claim 27, further comprisingbubble traps in fluid communication with the plurality of sample wells.39. The test card of claim 38, wherein each of the plurality of samplewells are disposed fluidically between a respective one of the bubbletraps and a respective one of the first fluid flow distribution channeland the second fluid flow distribution channel.
 40. The test card ofclaim 27, wherein an average fluidic network distance between wells ofthe plurality of sample wells is from about 20 to about 25 mm.
 41. Thetest card of claim 27, wherein the average fluidic network distancebetween wells of the plurality of sample wells is less than 30 mm. 42.The test card of claim 27, wherein the card body further comprises athird distribution channel defined at the first surface, wherein thethird distribution channel is operatively connected to the seconddistribution channel disposed on the second surface via at least onethrough-channel.
 43. The test card of claim 42, wherein the card bodyfurther comprises a plurality of second fill channels disposed in thefirst surface of the test card and operatively connected to the thirddistribution channel and a third group of sample wells.
 44. The testcard of claim 27, further comprising a plurality of fill channelsconnected to the first fluid flow distribution channel between the firstfluid flow distribution channel and the first group of sample wells 45.The test card of claim 44, further comprising a plurality of diffusionbarriers in the plurality of fill channels, wherein the plurality ofdiffusion barriers are operable to interrupt fluid flow between one ormore opposing sample wells of the first group of sample wells.
 46. Thetest card of claim 45, wherein the plurality of diffusion barriers havea width of about 1.2 mm and a height of about 2 mm.
 47. The test card ofclaim 45, wherein the first fluid flow distribution channel furthercomprises a diffusion zone, and wherein the diffusion zone has a widthof about 2 mm, a height of about 2mm, and a depth of about 0.6 mm. 48.The test card of claim 47, wherein the diffusion zone has a volume ofabout 2.4 mm³.
 49. A method of filling a test card with a fluid samplecomprising directing the fluid sample into the fluid intake port of thetest card of claim 27, wherein the test card is configured to direct afirst portion of the fluid sample to the first group of sample wells viathe first fluid flow distribution channel, and wherein the test card isconfigured to direct a second portion of the fluid sample to the secondgroup of sample wells via the second fluid flow distribution channel.